Kienbock's Disease

The lunate bone is one of the small bones in the wrist. The lunate bone is part of the proximal carpal row. It is part of the radiocarpal and midcarpal joints. The midcarpal joint allows your hand and wrist to move upwards and towards the thumb side. The radiocarpal joint allows you to lower your hand and wrist and move it towards the little finger side of your hand.

The exact cause of Kienbock’s disease is unknown.  It occurs when the blood supply to the lunate bone is disrupted.  Your bones need blood to live.  Without a blood supply, the lunate bone decays and dies.  Kienbock’s disease can eventually affect the structure and function of the wrist.

Blood flow to the lunate bone may be disrupted by trauma, such as a fall.  Overuse of the dominant hand is suspected to contribute to Kienbock’s disease.  People that are born with just one artery to supply the lunate, instead of two, are at risk for developing Kienbock’s disease.

Kienbock’s disease affects more men than women.  It most frequently develops in individuals between the ages of 20 and 40 years old.  It appears to develop more commonly in the dominant hand.

The initial symptom of Kienbock’s disease is pain.  Kienbock’s disease can cause your wrist to feel painful, stiff, and tender. Your wrist may appear swollen. You may not be able to move your wrist as far as you used to be able to. Your hand and grip strength may become weaker, making it difficult for you to hold objects.

Kienbock’s disease is a progressive condition, meaning that it can get worse over time.  As the lunate bone degenerates, symptoms may become worse.  Kienbock’s disease can lead to arthritis and loss of wrist function.

Your doctor can diagnose Kienbock’s disease by examining your wrist and conducting tests.  You should tell your doctor about your symptoms and any recent trauma to your hand.  Your doctor will take an X-ray of your wrist. X-rays may be normal during the initial stages of Kienbock’s disease.  An MRI scan or CT scan may be used to show more detailed images.

Your doctor will determine what stage your Kienbock’s disease is in.  The condition specifically progresses through four stages. In the first stage, X-ray may be normal and symptoms are similar to a sprained wrist.  In stage two, the lunate bone hardens.  This can be seen on xray.  Pain, swelling, and tenderness increase.  In the third stage, the lunate bone collapses and breaks into pieces. T he other bones in the wrist may shift position as the lunate bone deteriorates.  People with stage three Kienbock’s disease experience an increase in symptoms plus grip weakness and limited movement of their wrist.  In the final stage of Kienbock’s disease, the surfaces of nearby bones are affected, and arthritis develops in the wrist.

The treatment that you receive will depend on the stage of Kienbock’s disease that you have.  For beginning stages, splints or casts may relieve pressure on the lunate and restore the blood flow.  Medications may help ease pain and reduce swelling.  More advanced stages of Kienbock’s disease may be treated with surgery.

There are several surgical options for Kienbock’s disease.   The most appropriate choice for you depends on the stage of your condition, your activity level, and your expected outcome.  Your surgeon will discuss options with you.  In some cases, the blood supply can be surgically restored to the lunate bone.  This type of procedure is called revascularization surgery. In another surgical procedure, lengthening or shortening the lower arm bones can reduce the pressure on the lunate.  Bones are made longer with bone grafts.  Bones are made shorter by removing a section of the bone. These are referred to as joint leveling procedures.

A severely damaged lunate bone can be removed.  The bones on each side of the lunate may also be removed in a procedure called a proximal row carpectomy.  This surgery can help to relieve pain while allowing partial wrist movement.

Another type of surgery involves fusing, a procedure that connects several small bones in the wrist.  Fusion can relieve pressure on the lunate.  Fusion does not improve wrist movement.  If arthritis is present, fusion can help relieve pain and maintain the wrist movement that you have.

Kienbock’s disease is a progressive condition that gets worse over time.  There is no cure for Kienbock’s disease.  However, surgical and nonsurgical treatments can relieve symptoms, maintain motion, and sustain wrist function.